Through-hull fittings pass hoses through the hull for bilge discharge, livewell intake, and washdown lines. Match outlet size to pump discharge and hose ID.
Hose Size Matching
Common bilge pumps use 3/4" or 1-1/8" outlets. Verify hose barb diameter before ordering fittings.
Bronze vs Nylon
Bronze suits below-waterline through-hulls on larger vessels. Nylon and ABS options work for many above-water scupper and drain applications.
Check Valves
Angled fittings with integrated check valves prevent back-siphon into the bilge when discharge sits above the waterline.
Below-Waterline Rules
Follow ABYC guidance for seacocks and backing plates on critical penetrations. Shop thru-hull fittings.
